1. Field of the Invention
This invention relates to a support pole for supporting lights, antennas, cameras, etc., and more particularly to a square-tube type support pole having a bell-shaped lower end portion.
2. Description of the Related Art
Support poles such as poles for supporting lights, antennas, cameras, etc., or the like, are commonly constructed so as to have a square-tube cross-section. The support pole is normally comprised of an elongated pole member having its lower end welded to a flat base plate which is anchored to a suitable footing or the like.
Although the square-tube support poles experience a higher rate of structural failure than poles having a round cross-section, the square-tube poles are perhaps the most widely used poles in the support pole industry.
It has been discovered that the lower ends of the square-tube poles develop fractures or cracks therein adjacent the corners thereof. It is believed that such fractures or cracks are due to metal fatigue and that the cracks and fractures are the primary reason for the structural failure of the poles.